bigdata-commit Mailing List for Blazegraph (powered by bigdata) (Page 31)

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Revision: 7982
          http://sourceforge.net/p/bigdata/code/7982
Author:   thompsonbry
Date:     2014-03-15 14:00:37 +0000 (Sat, 15 Mar 2014)
Log Message:
-----------
Replaced the concept of directedTraversal:boolean with the more general concept of TraversalDirection.  The TraversalDirection is a type safe enum with three possible values Forward, Reverse, and Undirected. This generalizes the concept of directed versus undirected traversal and adds support for reverse traversal.

Added a unit test for this.

Updated the wiki page to reflect the changed API.

Modified Paths:
--------------
    branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/IGASContext.java
    branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/impl/GASContext.java
    branches/RDR/bigdata-gas/src/test/com/bigdata/rdf/graph/analytics/TestBFS.java
    branches/RDR/bigdata-rdf/src/java/com/bigdata/rdf/graph/impl/bd/GASService.java

Added Paths:
-----------
    branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/TraversalDirectionEnum.java

Modified: branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/IGASContext.java
===================================================================

--- branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/IGASContext.java	2014-03-15 13:31:34 UTC (rev 7981)
+++ branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/IGASContext.java	2014-03-15 14:00:37 UTC (rev 7982)
@@ -67,20 +67,22 @@
     IGraphAccessor getGraphAccessor();
 
     /**
-     * Specify whether the visited edges of the graph are to be interpreted as
-     * directed or undirected (default <code>directed</code>).
+     * Specify the traversal direction for the {@link IGASProgram}.
      * <p>
      * The value specified here is used to determine how the {@link EdgesEnum}
-     * will be interpreted for the GATHER and SCATTER phases. See
-     * {@link EdgesEnum#asUndirectedTraversal()}.
+     * will be interpreted for the GATHER and SCATTER phases. The default is
+     * {@link TraversalDirectionEnum#Forward}.
+     * 
+     * @see TraversalDirectionEnum#asTraversed(EdgesEnum)
+     * @see EdgesEnum#asUndirectedTraversal()
      */
-    void setDirectedTraversal(boolean newVal);
+    void setTraversalDirection(TraversalDirectionEnum newVal);
 
     /**
-     * Return <code>true</code> if the graph should be interpreted as a directed
-     * graph.
+     * Return a type safe value indicating the traversal direction for the
+     * {@link IGASProgram}.
      */
-    boolean isDirectedTraversal();
+    TraversalDirectionEnum getTraversalDirection();
     
     /**
      * Specify the maximum number of iterations for the algorithm. A value of

Added: branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/TraversalDirectionEnum.java
===================================================================
--- branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/TraversalDirectionEnum.java	                        (rev 0)
+++ branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/TraversalDirectionEnum.java	2014-03-15 14:00:37 UTC (rev 7982)
@@ -0,0 +1,76 @@
+/**
+   Copyright (C) SYSTAP, LLC 2006-2012.  All rights reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+package com.bigdata.rdf.graph;
+
+/**
+ * Typesafe enumeration of manner in which an RDF graph will be traversed by an
+ * {@link IGASProgram} based on its {@link EdgesEnum}.
+ * 
+ * @author <a href="mailto:tho...@us...">Bryan Thompson</a>
+ */
+public enum TraversalDirectionEnum {
+
+    /**
+     * Directed traversal along the natural direction of the RDF statements
+     * (from Subject to Object).
+     */
+    Forward,
+    /**
+     * Directed traversal along the reverse direction of the RDF statements
+     * (from Object to Subject).
+     */
+    Reverse,
+    /**
+     * Undirected traversal - edges are explored in both the {@link #Forward}
+     * and the {@link #Reverse} direction.
+     */
+    Undirected;
+
+    /**
+     * Interpret the given {@link EdgesEnum}, returning the effective value
+     * required to impose the semantics of this {@link TraversalDirectionEnum}.
+     * 
+     * @param edges
+     *            The {@link EdgesEnum}.
+     *            
+     * @return The effective {@link EdgesEnum} value that will impose the
+     *         traversal semantics of this {@link TraversalDirectionEnum}.
+     *         
+     * @see EdgesEnum#asUndirectedTraversal()
+     */
+    public EdgesEnum asTraversed(final EdgesEnum edges) {
+
+        switch (this) {
+        case Forward:
+            return edges;
+        case Reverse:
+            switch (edges) {
+            case InEdges:
+                return EdgesEnum.OutEdges;
+            case OutEdges:
+                return EdgesEnum.InEdges;
+            default:
+                return edges;
+            }
+        case Undirected:
+            return edges.asUndirectedTraversal();
+        default:
+            throw new AssertionError();
+        }
+
+    }
+
+}

Modified: branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/impl/GASContext.java
===================================================================
--- branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/impl/GASContext.java	2014-03-15 13:31:34 UTC (rev 7981)
+++ branches/RDR/bigdata-gas/src/java/com/bigdata/rdf/graph/impl/GASContext.java	2014-03-15 14:00:37 UTC (rev 7982)
@@ -19,7 +19,6 @@
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -37,6 +36,7 @@
 import com.bigdata.rdf.graph.IGraphAccessor;
 import com.bigdata.rdf.graph.IReducer;
 import com.bigdata.rdf.graph.IStaticFrontier;
+import com.bigdata.rdf.graph.TraversalDirectionEnum;
 import com.bigdata.rdf.graph.util.GASUtil;
 
 import cutthecrap.utils.striterators.Filter;
@@ -65,9 +65,10 @@
 
     /**
      * Whether or not the edges of the graph will be traversed with directed
-     * graph semantics (default is TRUE).
+     * graph semantics (default is {@link TraversalDirectionEnum#Forward}).
      */
-    private final AtomicBoolean directedGraph = new AtomicBoolean(true);
+    private final AtomicReference<TraversalDirectionEnum> traversalDirection = new AtomicReference<TraversalDirectionEnum>(
+            TraversalDirectionEnum.Forward);
     
     /**
      * The maximum number of iterations (defaults to {@link Integer#MAX_VALUE}).
@@ -258,12 +259,10 @@
          * APPLY is done before the SCATTER - this would not work if we pushed
          * down the APPLY into the SCATTER).
          */
-        final EdgesEnum gatherEdges = isDirectedTraversal() ? program
-                .getGatherEdges() : program.getGatherEdges()
-                .asUndirectedTraversal();
-        final EdgesEnum scatterEdges = isDirectedTraversal() ? program
-                .getScatterEdges() : program.getScatterEdges()
-                .asUndirectedTraversal();
+        final EdgesEnum gatherEdges = getTraversalDirection().asTraversed(
+                program.getGatherEdges());
+        final EdgesEnum scatterEdges = getTraversalDirection().asTraversed(
+                program.getScatterEdges());
         final boolean pushDownApplyInGather;
         final boolean pushDownApplyInScatter;
         final boolean runApplyStage;
@@ -816,17 +815,20 @@
     }
 
     @Override
-    public boolean isDirectedTraversal() {
-    
-        return directedGraph.get();
-        
+    public TraversalDirectionEnum getTraversalDirection() {
+
+        return traversalDirection.get();
+
     }
-    
+
     @Override
-    public void setDirectedTraversal(final boolean newVal) {
+    public void setTraversalDirection(final TraversalDirectionEnum newVal) {
 
-        directedGraph.set(newVal);
-        
+        if (newVal == null)
+            throw new IllegalArgumentException();
+
+        traversalDirection.set(newVal);
+
     }
     
     @Override

Modified: branches/RDR/bigdata-gas/src/test/com/bigdata/rdf/graph/analytics/TestBFS.java
===================================================================
--- branches/RDR/bigdata-gas/src/test/com/bigdata/rdf/graph/analytics/TestBFS.java	2014-03-15 13:31:34 UTC (rev 7981)
+++ branches/RDR/bigdata-gas/src/test/com/bigdata/rdf/graph/analytics/TestBFS.java	2014-03-15 14:00:37 UTC (rev 7982)
@@ -21,6 +21,7 @@
 import com.bigdata.rdf.graph.IGASEngine;
 import com.bigdata.rdf.graph.IGASState;
 import com.bigdata.rdf.graph.IGraphAccessor;
+import com.bigdata.rdf.graph.TraversalDirectionEnum;
 import com.bigdata.rdf.graph.impl.sail.AbstractSailGraphTestCase;
 
 /**
@@ -104,11 +105,11 @@
 
     /**
      * Variant test in which we choose a vertex (<code>foaf:person</code>) in
-     * the middle of the graph and insist on directed edges. Since the edges
-     * point from the person to the <code>foaf:person</code> vertex, this BSF
-     * traversal does not discover any connected vertices.
+     * the middle of the graph and insist on forward directed edges. Since the
+     * edges point from the person to the <code>foaf:person</code> vertex, this
+     * BSF traversal does not discover any connected vertices.
      */
-    public void testBFS_directed() throws Exception {
+    public void testBFS_directed_forward() throws Exception {
 
         final SmallGraphProblem p = setupSmallGraphProblem();
 
@@ -135,7 +136,8 @@
                 gasState.setFrontier(gasContext, p.getFoafPerson());
 
                 // directed traversal.
-                gasContext.setDirectedTraversal(true);
+                gasContext
+                        .setTraversalDirection(TraversalDirectionEnum.Forward);
                 
                 // Converge.
                 gasContext.call();
@@ -177,6 +179,83 @@
 
     /**
      * Variant test in which we choose a vertex (<code>foaf:person</code>) in
+     * the middle of the graph and insist on reverse directed edges. Since the
+     * edges point from the person to the <code>foaf:person</code> vertex,
+     * forward BSF traversal does not discover any connected vertices. However,
+     * since the traversal direction is reversed, the vertices are all one hop
+     * away.
+     */
+    public void testBFS_directed_reverse() throws Exception {
+
+        final SmallGraphProblem p = setupSmallGraphProblem();
+
+        final IGASEngine gasEngine = getGraphFixture()
+                .newGASEngine(1/* nthreads */);
+
+        try {
+
+            final SailConnection cxn = getGraphFixture().getSail()
+                    .getConnection();
+
+            try {
+
+                final IGraphAccessor graphAccessor = getGraphFixture()
+                        .newGraphAccessor(cxn);
+
+                final IGASContext<BFS.VS, BFS.ES, Void> gasContext = gasEngine
+                        .newGASContext(graphAccessor, new BFS());
+
+                final IGASState<BFS.VS, BFS.ES, Void> gasState = gasContext
+                        .getGASState();
+
+                // Initialize the froniter.
+                gasState.setFrontier(gasContext, p.getFoafPerson());
+
+                // directed traversal.
+                gasContext
+                        .setTraversalDirection(TraversalDirectionEnum.Reverse);
+                
+                // Converge.
+                gasContext.call();
+
+                // starting vertex at (0,null).
+                assertEquals(0, gasState.getState(p.getFoafPerson()).depth());
+                assertEquals(null, gasState.getState(p.getFoafPerson())
+                        .predecessor());
+
+                // All other vertices are 1-hop.
+                assertEquals(1, gasState.getState(p.getMike()).depth());
+                assertEquals(p.getFoafPerson(), gasState.getState(p.getMike())
+                        .predecessor());
+
+                assertEquals(1, gasState.getState(p.getBryan()).depth());
+                assertEquals(p.getFoafPerson(), gasState.getState(p.getBryan())
+                        .predecessor());
+
+                assertEquals(1, gasState.getState(p.getMartyn()).depth());
+                assertEquals(p.getFoafPerson(), gasState
+                        .getState(p.getMartyn()).predecessor());
+
+            } finally {
+    
+                try {
+                    cxn.rollback();
+                } finally {
+                    cxn.close();
+                }
+                
+            }
+
+        } finally {
+
+            gasEngine.shutdownNow();
+
+        }
+    
+    }
+
+    /**
+     * Variant test in which we choose a vertex (<code>foaf:person</code>) in
      * the middle of the graph and insist on directed edges. Since the edges
      * point from the person to the <code>foaf:person</code> vertex, this BSF
      * traversal does not discover any connected vertices.
@@ -208,8 +287,9 @@
                 gasState.setFrontier(gasContext, p.getFoafPerson());
 
                 // undirected traversal.
-                gasContext.setDirectedTraversal(false);
-                
+                gasContext
+                        .setTraversalDirection(TraversalDirectionEnum.Undirected);
+
                 // Converge.
                 gasContext.call();
 

Modified: branches/RDR/bigdata-rdf/src/java/com/bigdata/rdf/graph/impl/bd/GASService.java
===================================================================
--- branches/RDR/bigdata-rdf/src/java/com/bigdata/rdf/graph/impl/bd/GASService.java	2014-03-15 13:31:34 UTC (rev 7981)
+++ branches/RDR/bigdata-rdf/src/java/com/bigdata/rdf/graph/impl/bd/GASService.java	2014-03-15 14:00:37 UTC (rev 7982)
@@ -55,6 +55,7 @@
 import com.bigdata.rdf.graph.IGraphAccessor;
 import com.bigdata.rdf.graph.IPredecessor;
 import com.bigdata.rdf.graph.IReducer;
+import com.bigdata.rdf.graph.TraversalDirectionEnum;
 import com.bigdata.rdf.graph.analytics.CC;
 import com.bigdata.rdf.graph.analytics.PR;
 import com.bigdata.rdf.graph.impl.GASEngine;
@@ -167,14 +168,19 @@
         int DEFAULT_NTHREADS = 4;
 
         /**
-         * This option determines whether the traversal of the graph will
-         * interpret the edges as directed or undirected.
+         * This option determines the traversal direction semantics for the
+         * {@link IGASProgram} against the graph, including whether the the
+         * edges of the graph will be interpreted as directed (
+         * {@link TraversalDirectionEnum#Forward} (which is the default),
+         * {@link TraversalDirectionEnum#Reverse}), or
+         * {@link TraversalDirectionEnum#Undirected}.
          * 
-         * @see IGASContext#setDirectedTraversal(boolean)
+         * @see TraversalDirectionEnum
+         * @see IGASContext#setTraversalDirection(TraversalDirectionEnum)
          */
-        URI DIRECTED_TRAVERSAL = new URIImpl(NAMESPACE + "directedTraversal");
+        URI TRAVERSAL_DIRECTION = new URIImpl(NAMESPACE + "traversalDirection");
         
-        boolean DEFAULT_DIRECTED_TRAVERSAL = true;
+        TraversalDirectionEnum DEFAULT_DIRECTED_TRAVERSAL = TraversalDirectionEnum.Forward;
         
         /**
          * The maximum #of iterations for the GAS program (optional, default
@@ -398,7 +404,7 @@
         
         // options extracted from the SERVICE's graph pattern.
         private final int nthreads;
-        private final boolean directedTraversal;
+        private final TraversalDirectionEnum traversalDirection;
         private final int maxIterations;
         private final int maxVisited;
         private final URI linkType, linkAttrType;
@@ -433,10 +439,13 @@
                     store.getValueFactory().createLiteral(
                             Options.DEFAULT_NTHREADS))).intValue();
 
-            this.directedTraversal = ((Literal) getOnlyArg(Options.PROGRAM,
-                    Options.DIRECTED_TRAVERSAL, store.getValueFactory()
-                            .createLiteral(Options.DEFAULT_DIRECTED_TRAVERSAL)))
-                    .booleanValue();
+            this.traversalDirection = TraversalDirectionEnum
+                    .valueOf(((Literal) getOnlyArg(
+                            Options.PROGRAM,
+                            Options.TRAVERSAL_DIRECTION,
+                            store.getValueFactory().createLiteral(
+                                    Options.DEFAULT_DIRECTED_TRAVERSAL.name())))
+                            .stringValue());
 
             this.maxIterations = ((Literal) getOnlyArg(Options.PROGRAM,
                     Options.MAX_ITERATIONS, store.getValueFactory()
@@ -761,7 +770,7 @@
                 final IGASContext<VS, ES, ST> gasContext = gasEngine.newGASContext(
                         graphAccessor, gasProgram);
 
-                gasContext.setDirectedTraversal(directedTraversal);
+                gasContext.setTraversalDirection(traversalDirection);
                 
                 gasContext.setMaxIterations(maxIterations);
 

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